Recombinant proteins containing a short stretch of contiguous Histidine residues can be used to specially bind to N-nitrilotriacetic acid chelated nickel ions, providing a general method for protein purification. E. Kubalek used a lipid derivatized with a Nickel-chelating head group to induce crystallization of His-tagged proteins using monolayer method. Low resolution map has been obtained by HIV RT and we will continue to explore this method in an attempt to study different mutant proteins of HIV RT that Dr. Le Grice has generated.